The invention relates to a magazine for a surgical clip applicator comprising a receiving chamber for clips which are arranged one behind the other and displaceable in the receiving chamber towards its open end, these clips having two arms which are connected via a bridge and pivotable away from one another into an open position contrary to an elastic force and projections which are associated with these arms and project rearwards beyond the bridge, and comprising two opening tools which are located opposite one another, are movable towards one another like pincers and can be abutted on the projections of the respectively foremost clip.
Magazines of this type are used to apply a larger number of clips from them, for example, for clamping the scalp during operations on the head. For this purpose, clip applicators with magazines are already known, in which the clips are stored one behind the other and from which the clips are moved forwards in steps. The respectively foremost clip is grasped by pincer-like opening tools which are movable on clip applicators of this type and mounted stationarily, and these pincer-like opening tools open the clip and apply it at the desired location (DE-PS 37 04 760). With devices of this type the opening tools are part of the devices, only the magazines with the clips accommodated therein can be exchanged.
The object of the invention is to design a generic magazine such that the construction of clip applicators of this type can, altogether, be simplified, in particular, due to the fact that the clip applicators do not require their own mechanism for opening and applying the clips.
This object is accomplished in accordance with the invention, in a magazine of the type described at the outset, in that the opening tools are connected in a hinge-like manner to an advancing element displaceable in the magazine parallel to the direction of displacement of the clips and come to rest on a deflection surface of the magazine during the advancing movement of this advancing element in the direction towards the open end of the receiving chamber and are thereby pivoted inwards transversely to the direction of displacement towards the opening tool located respectively opposite.
With such a solution, the opening tools designed as hinge elements are thus part of the magazine and they are mounted in a simple manner in that they are connected in a hinge-like manner to an advancing element displaceable in longitudinal direction of the magazine. The advancing movement of the advancing elements is utilized to pivot these hinge elements inwards, and this advancing movement is generated by the abutment of the opening tools, which are connected in a hinge-like manner to the advancing elements, on a deflection surface of the magazine. This results in a particularly simple construction not only of the magazine but also of the entire clip applicator since it is sufficient to provide a mechanism on the clip applicator which moves the advancing elements back and forth in the magazine. Special opening tools on the clip applicator itself are no longer necessary.
As a result of this construction, very considerable opening forces can also be generated since the hinge element and the advancing element interact in the manner of a knee joint. The advancing movement is translated into a very slight angular pivoting, in particular, at the end of the advancing movement, and this very slight angular pivoting movement leads to a slight displacement of the opening tool on the clip to be opened, i.e. a reduction in the path of displacement occurs and thus an increase in the corresponding displacement force. The opening forces directed inwards are, for the rest, essentially taken over by the guide means for the advancing element, against which the advancing element abuts and on which the advancing element is thus supported.
It is particularly advantageous when the opening tools are pivotable outwards contrary to an elastic restoring force which is smaller than the force required to open the clips. As a result of this restoring force, the opening tools are pivoted inwards against the clips and abut with their free edges on the clips, in particular, on the projections of the respectively foremost clip but they do not yet open the clip since this elastic restoring force is smaller than the required opening force. This elastic abutment of the opening tools on the foremost clip results in the foremost clip being held between the opening tools until it is moved forwards into the application position.
A particularly advantageous development results when the opening tools are connected to the advancing elements in one piece via a weakened hinge area.
The opening tools and the advancing element can then consist, in particular, of a flexible plastic material so that a cheap construction of the magazine, which can, in this case, also be produced as a disposable part, results.
In accordance with a preferred embodiment it is provided for the deflection surface to be formed by the end wall of the magazine adjoining the open end of the receiving chamber on both sides.
A particularly advantageous construction results when the advancing element has entraining members which can be abutted on the clips for the step-wise advancement of the clips.
The advancing element thus undertakes an additional function, namely that of advancing all the clips which are stored in the magazine and which are moved forwards by the length of a clip with each advancing movement of the advancing element, wherein this advancing movement of the advancing elements also causes the closure of the opening tools at the same time.
In a preferred embodiment it is provided for the opening tools to abut on the projections of the foremost clip during the advancement of the advancing elements before the entraining members of the advancing element abut on following clips. As a result, the respectively foremost clip is moved further forwards than the remaining clips and thus is at a distance from the following clip which is sufficient for the insertion of the opening tools.
The entraining members are designed to be able to disengage from the receiving chamber so that the clips moved forward during the advancement of the advancing element are not drawn back again during the return movement of the advancing elements. The entraining members can thereby be disengaged from the receiving chamber in different ways; in a preferred embodiment it is provided for the entraining members to slide elastically along the clips when the advancing element is withdrawn, i.e., in this case, the clips themselves press the entraining members elastically outwards.
The entraining members can be designed, in particular, as spring tongues which protrude at an angle into the receiving chamber in the direction of advancement. Apart from the entraining function, the spring tongues also have the task with this construction of guiding the clips along their path of displacement and securing them against any tilting.
In a preferred embodiment it is provided for the advancing elements to be designed as half shells which together form the channel-like receiving chamber for the clips.
These half shells are fixed in position relative to one another in the direction of advancement, for example, by means of projections and undercuts interacting in a positive manner so that during the displacement of one advancing element in longitudinal direction the other advancing element is automatically taken along.
In this respect, it is advantageous when the half shells are mounted in an elongated housing of the magazine for displacement in its longitudinal direction.
In this respect, it may be provided for the half shells to be held in mutual abutment by the housing. As a result, a guidance of the half shells by the housing surrounding the half shells is, on the one hand, brought about; on the other hand, it is not necessary to permanently connect the two half shells securely to one another, the abutment by means of the surrounding housing is sufficient to fix the two half shells in position surrounding the clips.
The clips may be secured in position in the receiving chamber against any undesired rearward displacement in various ways, for example, by means of frictional engagement with the side walls.
In accordance with a particularly preferred embodiment, it is provided for retaining projections for the clips, which can be disengaged from the receiving chamber and are fixed in position in longitudinal direction of the magazine, to protrude into the receiving chamber. These are arranged such that the clips can be displaced forwards when the retaining projections are disengaged but are prevented from moving back when the retaining projections are engaged.
The retaining projections may, in particular, be movable flexibly out of the receiving chamber, i.e. the clips press the retaining projections flexibly out of the receiving chamber during advancement but abut on the retaining projections engaged in the receiving chamber during any rearward movement.
It is advantageous when the retaining projections are spring tongues which protrude at an angle into the receiving chamber in the direction of advancement.
In a preferred embodiment, the retaining projections are arranged on the side walls of the receiving chamber. An arrangement then results, with which the entraining members of the advancing elements are, for example, arranged on the upper side and the underside of the clips, the retaining projections, on the other hand, on the two side walls.
It is advantageous when the retaining projections are held on supports which are inserted laterally into the receiving chamber and fixed in position on the magazine so as to be axially non-displaceable. In this respect, these may, for example, be metal strips which have notches bent elastically inwards as retaining projections.
In accordance with a preferred embodiment it is provided for the advancing elements to have on their outer side recesses which adjoin one another in longitudinal direction and in which a transport entrainment means engages which can be displaced back and forth in the direction of displacement of the clips. This transport entrainment means displaces the advancing elements reciprocatingly back and forth in the magazine, wherein, on the one hand, the clips are moved forwards each time by one step while, on the other hand, the respectively foremost clip is opened for application and closed again.
It is favorable when the base of the recess is separated from the advancing element on three sides and forms the entraining member for the clips protruding into the receiving chamber. This results in a particularly simple, constructional design for the advancing elements.